Tread plate



0a. 17, 193.9. H E L SR 2,176,849

TREAD PLATE Filed Dec. 5, 1938 INVENTOR. z/o/l/v SCHMELLEI? 6/: Y

ATTORNEYS.

' wellasalongperiod-of 1o larly aluminum or that the rate of wear ciently greater than the rate of wear upon the 1 as a non-slipping surface John else-fourth to 22's 0152"; Schindler, Boob PATENT orrlcs.

John L.

one-fourth to Frank 'I. River, Ohio Application December 5. less, Serial No. more 90laims.

run invention,'asindicated,.relates to a tread plate. More particularly; it comprises a composite plate adapted for a wide variety of uses. wherein 'a non-slipping surface is desirable, as

,ularly, the invention relates to a plate wherein material having abrasive characteristics as well as a high degree (if-hardness is embodied in av plate formed of relatively-soft metal. particualuminum alloys. .It has been found that-.aluminum and aluminum alloys and the like, when combined with material such as carborundum or similar exceptionally adapted for holding such abrasives infirm engagement throughout the period of use ofm the wear plate and found that atno time durthe service llfe of the plate is there a tendency to develop smooth slippery surfaces over all or any portion of the of the abrasive substance to maintain a slight projection of such abrasive material above the surface of the aluminum area of the plate, so that at all 3 times there is presented an abrasive tread su.r.

face to prevent slipping upon such surface. It has also been found that plates formed in the manner hereinafter set forth havewear edges particularly pted to resist being worn to a a dangerous which is so frequently the cause of accidents on tread plates intended for heavy traific. r

The principal object of "the present invention is to form'an improved tread plate or plate with wherein abrasive surface is provided and maintained throughout the service life of such plates. I

' Another object of the invention is to provide a treadplate or-non-slipping surface of such character that high speed production may be carried on with absence of defects such as porous areas over the product and with uniform distribution ofctthe abrasive materialembodied in such produ as Another object of the invention is to provide a wear plate adapteg for heavy service conditions and having excepti nal capacity to'resist wear. Another object of the invention is to provide wear,plates having substantially uniform distrilo bution of abrasive material throughout the area of the plate and having the metal forming the body of the plate free of porous and defective areas.

Another obiect of the invention is to provide Is a weal-plate having abrasive material distributed service life.- More panic-- abrasive products, is

plate. It has been found aluminum is suifithroughout the body of the the corner edges thereof I her that such dges will not.wearto a smooth surface and wherein the plates through reversing may provide four wear edges before the plate is 8.

Other and further objects of the invention will talgpear in the course of the following descripn. 4 v To the accomplishment of the foregoing and D related ends, said invention. then, consists of the means hereinafter fully described and particularly pointed out in the claims, .the annexed' drawing and the following description setting structures embodying the II disposed means constituting, however. but several of various forms in which the principle of the invention maybe used. Ihsaid annexedv wing: Figure 1 is a central vertical sectional view showing a sand mold having a wear plate structure and multiple sprues therewith; Figure 2 is a perspective'view of the wear plate and accessory metal used in forming the same as it appears when removed from the mold shown in Figure 1; j Figure 3 is a fragmentary perspective view showing a section of the finished wear plate wherein small particles of abrasive material are distributed throughout the body of the plate. so Figure 4 is an enlarged view of the plate shown in'Fig'ures 2 and 8. wherein smallpartlcles of abrasive material are utilised, such view being 'taken along the line H shown in Figure 2,

looking in the direction ofthe arrows; l='igure5isaviewsimilart0Figure-i,wherein larger particles of abrasive material are utilized, such particles extending completely through the plate in a vertical direction:

Plate s m a uniformly in such men- Figure, 6 is aperspective view of a modified 40' sbrasive particles may be of relatively small dillmensions, as shown in the enlarged view in Fig ure 4, or larger particles 4 may be used as illussive particlesheld in a binder formed of abrasive material, such blocks preferably being of -a size 'of the full height of the plate and being held within the body of the plate I formed of alu- 'minum or aluminum alloys. It will be noted that the plate shown in Figure 6 presents at its respective longitudinal edges a larger extent of abrasive material than. of exposedbody metal, and that the edges are smooth and not ragged. This construction avoids the fracturing of the wear edge of the plate and introducing hazards when such plates are used for pedestrian traflic. It has been found desirable in forming plates of the type illustrated in Figure 6 to have the transverse elements of the plates of lesser width than the longitudinal elements. Thus the transverse metal strips 8 may be of a width of one fourth of an inch when the longitudinal strips 9. are formed of a width of one half inch. It is of less importance as to the width of the transverse strips 3 0. Ni over the intermediate areas of the plate, but

by having all of the transverse strips of substanftially uniform width, a better appearance is brought about and! standard sizes of composite blocks maybe used in the production of the plate structures.

The sprue passageways connecting with the plate proper, when communicating with the ends of the casting cavity, have the disadvantage of ,Araving a long path of travel to reach the central 4? areas of the plate and the loss of heat may in some instances be so great'as to cause porosity at such central areas, or on the other hand the rate of flow may be sufficiently strong to displace particles of abrasive material disposed in the casting 45 cavity preliminary to the pouring of the body In order to avoid displace;-

metalof the plate. ment of the abrasive material and excessive cooling of the metal before it has reached its final position within the mold cavity, it has been found 50 desirable to supply the metal for the body portion of the plate through sprue cavities of the type shown in Figure 1 wherein multiple ,sprue passageways are provided. The mold used is preferably a sand mold, the flask I I having a cope por- 55 tion I2 and a drag portion H. \The casting cavity H! for the plate is formed partly in the sand of the cope and drag portions substantially equally above and below the parting line I. It has been found desirable to have a plurality of 0 pouring passageways, and for a plate of the size,

illustrated in Figure 1, wherein the plate is of a width of seven inches and a length of approximately thirty-six inches and of a thickness or height of three eighths of an inch, to provide ap- 5 proximately three. points for the introduction of the metal for the body, such metal being preferably, as stated, of aluminum or aluminum alloys. Preliminary to assembling the mold, the particles. of abrasive material 3 are inserted therein 70 and the pouring passageways are formed through the material in the cope, such passageways preferably having a large bowl-like opening I to receive a substantial supply of metal and the bottom of such bowl-like area being connected by a 75 series of small passageways H, in the instanceshown four in number, such passageways being inclined slightly outwardly and having at their lower ends flared areas {8 so as to provide for .a series of relatively small passageways for the .entrance of the metal into the casting-chamber, 5

such passageways being spaced from each other a sufllcient distance to prevent interference of the metal streams entering the casting cavity and having a gentle rate of flow yet a relatively highrate of supply of metal to the casting cavity. In 10 this manner the more fluent metal substantially free of oxide particlesreaches the casting cavity at a plurality of points, in the instance shown at twelve spaced points closely adjacent the central area of the plate, and the flow of metal reaches 15 all portions of the plate while still in free flow- .ing condition so that porous areas are entirely avoided and a product of substantially uniform characteristics throughout is formed. I

Where blocks of material are used as shown in g Figure 6, the position of the multiple pouring sprue passageways I1 is arranged so that the flared openings l8 at the baseof such passageways are at points intermediate the blocks so that the metal of the'body will flow through the inter- 25 secting passageways forming the various bars Q,

9 and Ill, heretofore referred to. Upon the removal of the casting from the sand mold, the excess metal will be detached from the surface of the plate by fracturing the same and later grindo ing or cutting away any residual portions projecting therefrom. The plates, when formed in the manner set forth, will exhibit a remarkably uniform distribution of abrasive material throughout the piate body, as to all the surfaces thereof, including the edge portions which are subjected to the highest degree of wear. I

In instances where extraordinarilyheavy traffic takes place, as in large cities having loading plat- 40 forms for railways or other vehicles, stores, and thoroughfares for pedestrian traffic wherein stairs or ramps or the like are utilized, the plate may be formed in the manner shown in Figures '6 and 7. Where stair treads are necessary for such thoroughfares, the heaviest wear occurs at the exposed outerv edge of the wear plate, and in such instances the pre-formed blocks are closely set, those at the edges particularly having a small edge of separation from each other and presenting a substantially uniform, area of abrasive surface over the entire exposed wearing edge of the plate. I

In all instances, whether the plates are the type illustrated in Figures 1 to 5, or in 6 and 7, it will be found that the rate of wear on the aluminum or aluminum alloy forming the body of the plate is sufflciently greater than the rate of wear on the abrasive material to insure at all. times a difference in the level of the body mateno rial and the abrasive material. Thus, plates of this character will present abrasive areas having a slight elevation above the remaining supporting surface of the plate, and in the case of rectangular blocks being utilized, as shown in Figure 6,

such projecting edges of abrasive material will be a surface for the body of the plate slightly below the surface of the abrasive material incorporated therein immediately upon the cooling of the cast metal plate, and this relative positioning of the aluminum body below the plane of the abrasive material is maintained throughout the life of the plate by reason of the greater wear-resisting .present when metals of other types qualities of the abrasive. The relation of the abrasive material and the aluminum body portion is such. that the firm engagement of the body' with the "adjacent abrasive surface will be of a very firm .character. However, with certain types of material it may be desirable to form channels II in the abrasive blocks with which key-ways" 22 of aluminum will be engaged after thecasting operation is completed, as shown in Figure There is no tendency whatsoever of the aluminum and the abrasive particles to crumble or disintegrate at the points of juncture, such as is are utilized, and there likewise is no tendency toward deformation of either the blocks of abrasive material or of the aluminum body portion under heavy duty service conditions.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the structure herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed. I

I therefore particularly point out and distinctly claim as my invention:

1. A wear. plate for stair treads and the like, having in combination a plurality of pre-formed elements of wear-resisting material, embodying abrasive fragments, of the full height of the plate structure and a web of aluminiferous material of like height interengaged with said units over lateral surfaces thereof.

2. A wear plate for stair treads and the like,

" having in combination a plurality of spaced preformed rectangular blocks of wear -resisting material, embodying abrasive fragments, of the full height of the plate structure and a web of aluminiferous material of like height interengaged with said units intermediate the surfaces of adjacently positioned blocks.

3. A wear plate for stair treads and the like,

having in combination a plurality of spaced preformed rectangular blocks of abrasive wear-resist-' ing material of the full height of the plate structure and a web of aluminiferous material of like height interengaged by means of recesses and proiections with said units intermediate the surfaces of adjacently positioned blocks.

4. A wear plate comprising a; cast aluminum metal body with wear-resisting elements embodying abrasive fragments engaged therein and distributed at intervals throughout said body, the metal of the body through shrinkage having. an outer surface lying below the plane of the outer most abrasive elements. I

5. A wear'plate comprising a cast aluminum metal body with wear-resisting elements embodying abrasive fragments engaged therein and dis-' tributed at intervals throughout said body,-the

outer surface lying below the plane of the outermost abrasive elements and being so maintained through relative wear ratio between said aluminum metal and said abrasive elements.

6. A 'wear plate comprising a body portion formed of a metal of high crystallization shrinkage and high heat transfer characteristics, of which the chief constituent is aluminum, with a plurality of abrasive wear-resisting fragments engaged therein and distributed throughout said body with exposed surfaces of said fragments appearing at intervals on at least one surfaceof such plate.

'7. A wear plate comprising a body portion formed of a metal of high crystallization shrinkage and high heat transfer characteristics, of which the chief constituent is aluminum with a plurality of abrasive wear-resisting fragments engaged therein and distributed throughout such body and with exposed surfaces of said fragments appearing at intervals on the marginal and upper and lower surfaces of said plate.

8. A wearplate comprising abrasive wear-resisting fragments in spaced relation to each other held firmly in a matrix and distributed throughout the same, such matrix formed of a metal of which the chief constituent is aluminum, such metal being of less wear-resisting capacity than said abrasive fragments and characterized by high crystallization shrinkage whereby permanent engagement with said fragments is provided.

. metal of the body through shrinkage having an 9. A wear plate comprising abrasive wear-re- I 

